DESCRIPTION (Investigator's Abstract): The goal of this Phase II project is to determine whether frozen red cells stored at 25 degrees Celsius for periods up to six months will have an in vivo survival equal to that of frozen red cells stored at -65 degrees Celsius for periods up to ten years, and will meet the criteria established by the Food and Drug Administration Office of Biological Research and Review for the blood product, "red blood cells frozen." During a Phase 1 project, several methods of glycerolizing red blood cells prior to freezing at -25 degrees Celsius were explored and methods of thawing these cells were also evaluated. Preliminary data from Phase 1 suggested that greater than 90 percent of red cell recovery could be achieved after -25 degrees Celsius storage for up to three months. The specific aim of the Phase 2 proposal is to evaluate stability of red blood cells cryopreserved by these methods over a twelve-month period. Red cell survival and recovery after transfusion will be assessed as well as biochemical characteristics, including 2/3 DPG and ATP levels to evaluate the products suitability for transfusion. The overall goal of the study is to develop technology to expand the capabilities of autologous blood donor programs to include the use of a simplified method for freezing preservation at - 25 degrees Celsius. The commercial potential of such a development would be considerable, in that institutions lacking sophisticated freezing and processing equipment for dealing with frozen blood requests could participate in this activity. Probably the most relevant application for this country would be in the area of autologous blood collection. Routine access to blood freezing technology would expand the interval between the time the first unit is collected and the time of the electric surgery. It may also have application in underdeveloped countries lacking sophisticated freezing equipment for maintenance of rare blood units.